 
    In such a case, the join would look like this:
 
+         (join has-a-and-b has-b-and-c {:b :blike}) =>
                                            #{{:a 1, :b 2, :blike 2, :c 1}
                                              {:a 1, :b 2, :blike 2, :c 2}
 

   in the last of the list of indexes, following keys to move from index to index.
   Example:

      (let [index:countries-by-person-id (subject/combined-index-on index:rulership-by-person-id
                                                                    :country_code
                                                                    index:country-by-country-code)]
        (subject/index-select 1 :using index:countries-by-person-id :keys [:gdp])
        => [{:gdp 1690}])

   (See ..someplace.. for details..)
  "
  {:arglists '([starting-index foreign-key next-index ...])}
  [starting-index & path-pairs]

  "Add more key/value pairs to `kvs`. They are found by looking up values
  in a [[one-to-one-index-on]] or [[one-to-many-index-on]] index.

  See [the wiki](https://github.com/marick/suchwow/wiki/such.relational) for examples.

  The `options` control what maps are returned and how they're merged into the
  original `kvs`. They may be given as N keys and values
  following the `kvs` argument (Smalltalk style) or as a single map. They are:

      :using <index>
        (required) The index to use.
      :via <key>
        (required) A single foreign key or a sequence of them that is used to
        look up a map in the <index>.
      :into <key>
        (optional, relevant only to a one-to-many map). Since a one-to-many map
        can't be merged into the `kvs`, it has to be added \"under\" (as the
        value of) a particular `key`.
      :keys [key1 key2 key3 ...]
        (optional) Keys you're interested in (default is all of them)
      :prefix <prefix>
        (optional) Prepend the given prefix to all the keys in the selected map.
        The prefix may be either a string or keyword. The resulting key will be
        of the same type (string or keyword) as the original.
  "

  ([kvs options]
